diff --git a/src/PrintNode/Request.php b/src/PrintNode/Request.php
index e87543d..4352cb5 100755
--- a/src/PrintNode/Request.php
+++ b/src/PrintNode/Request.php
@@ -240,7 +240,7 @@ public function getHeaders()
             $headers[] = 'X-Dont-Log: 1';
         }
         
-        return \array_merge($headers, $this->getCredentialHeader());
+        return \array_merge($headers, $this->getCredentialHeader(), $this->additionalHeaders);
         
     }